Heater unit



FIG. 1 is a perspective view showing our new design;

FIG. 2 is a top view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a right side view thereof;

FIG. 6 is a front view thereof; and,

FIG. 7 is a rear view thereof.

The broken line shown in the drawings are for the purpose of illustrating portions of the article and form no part of the claimed design. 

CLAIM The ornamental design for a heater unit, as shown and described. 